Re: [patch net-next RFC 0/4] introduce infrastructure for support of switch chip datapath

[Jiri Pirko <jiri@resnulli.us>]

Thu, Mar 20, 2014 at 12:49:07PM CET, jhs@mojatatu.com wrote:
>Hi Jiri,
>
>On 03/19/14 11:33, Jiri Pirko wrote:
>>This is just an early draft, RFC. I wanted to post this early to get the
>>feedback as soon as possible.
>>
>>The basic idea is to introduce a generic infractructure to support various
>>switch chips in kernel. Also the idea is to benefit of currently existing
>>Open vSwitch userspace infrastructure.
>>
>
>
>I think the abstraction should be a netdev and to be specific the
>bridge - not openvswitch. Our current tools like ifconfig, iproute2,
>bridge etc should continue to work.

That is exactly the case. Nothing is specific to OVS. OVS is just a one
method to access the switchdev api.

Abstraction is netdev. One netdev per each switch port and one netdev as
a master on the top of that representing the switch itself.


>In my experience, it is sufficient to model a switch after the linux
>bridge at the basic level if the starting point is
>L2 (which is the lowest common denominator).
>And then you add capabilities that different chips expose.
>Not every chip can do vxlan, flows etc. And we already know how
>to abstract those out.
>My  experience on top of broadcom chips is the approach i described
>works rather well.
>
>Additionally, note:
>We do have L2 devices that offload in the kernel
>(refer to DSA, posting earlier from the openwrt guys, and
>the intel devices which do VDMQ etc). I am now counting we have 5
>different approaches if we add yours.

I think that the problem is that each solution serves different purpose.
For example DSA is for switches connected as a PHY to a MAC. That is
completely different case to what my switchdev API is trying to handle.


>
>cheers,
>jamal
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